i'm creating a 3d airplane from a 2d plan. i have built the shell overlaying it over 2d plan. Now i need to rotate the plan -90deg to work on the tail and the wing. There is currently no option in the property panel to do this. where am i going wrong? Appreciate any feedback. thanks.
Assuming you have a blueprint which contains sections with both plan and elevation views, you can assign the same image as background to each relevant Blender orthographic view.
For example: Having constructed your shell from the blueprint's elevation section in the Blender's 'Left' view, you can add (Add Image) and assign the same blueprint image to Blender's 'Top' view. You don't have to reload it from file, it will already be in Blender's list of available images. You then offset/ rotate/reflect the blueprint image (in the Blender's background image panel) so that its plan section coincides with the shell you have built, seen from the top.
The versions of the background image are visible only from the exact preset Blender view to which they were assigned.
If the question is how to assign background images to different views Read:
If what you want to do is rotate the image used as background use the rotation options on the bacgkground images section.